In modern airplanes, more particularly civilian transport airplanes, fire extinguishers are provided.
Such devices, known for example from the Application FR 2864905, besides means for detecting the start of a fire and for controlling said device, have one or more reservoirs of extinguishing agent feeding a network to distribute the extinguishing agent to spray nozzles.
The reservoirs of extinguishing agent contain the extinguishing agent itself and means for pressurizing this extinguishing agent inside the reservoir, by means of a propelling agent, to permit its distribution at the desired time.
In practice, the reservoirs of extinguishing agent are often installed close to areas at risk of fire, such as hot zones where fuel circulates in the environment of the engines, or such as areas in which the impossibility of access in flight does not allow any other means of firefighting, for example the cargo compartments.
As an illustration that is particularly suitable for the applications of the disclosed embodiments, the case of an installation of a reservoir of fire extinguishing agent in an engine pylon is considered in the following description.
Thus, in airplanes that have engines attached beneath the wings by suspension pylons, it is beneficial to fasten the extinguishing agent reservoirs of the engine fire extinguishers inside the pylons, despite the numerous systems including cables and pipes passing through inside the pylons, and the size of the pylons which is reduced so as not to penalize the aerodynamics of the airplane.
Also, the extinguishing agent reservoirs must be the object of frequent checks in situ and in the workshop to verify their good condition, the volumes of extinguishing agent and of propelling agent inside them, and to be regularly reconditioned or replaced in case of their use.
Accordingly, the extinguishing agent reservoirs are necessarily capable of being taken down, and to that end, in particular when they are installed in a pylon, they are fastened to a fire extinguisher hanger structure, itself fastened to the inside of the principal structure of the pylon, from where said reservoirs can be removed or introduced through openings made in the side walls of the pylon, which openings are limited to a strict minimum because of the fact that said walls are generally working walls.
An example of a known extinguishing agent reservoir 1 is shown in FIG. 1a. An example of a hanger structure 2 is shown in FIG. 1b without the other parts of the principal structure of the pylon.
In all of the present description, the references to positioning the various elements are made considering said elements installed in a pylon of an airplane immobile on the ground; this is the case inter alia for the references “lower”, “upper”, “horizontal”, “vertical”, etc.
The hanger structure 2 in the pylon structure occupies principally a space located above the reservoirs 1.
The hanger structure 2 has an essentially horizontal chassis 20, beneath which are fastened a plurality of longitudinal crossbars 21. Each of said crossbars 21 has an essentially horizontal lower edge, and a reservoir 1 is fastened on the lower bearing surfaces of said lower edges of two adjacent crossbars 21.
A rail 22 is associated with each of said crossbars and forms a lateral guide beneath the crossbar 21 with which it is associated, which extends along said crossbar. For each pair of adjacent crossbars 21, two facing lateral slider bars are thus formed.
The extinguishing agent reservoir 1 has four metal fittings 10 intended to be fastened by fasteners, such as screws and nuts, to the lower bearing surfaces of the crossbars 21 of the hanger structure 2, which are positioned on the upper spherical head of the reservoir 1.
Each fitting 10 protrudes laterally on said upper spherical head, and has an edge forming a tenon, whose shape and dimensions are suitable for permitting said edge to slide in a lateral guide of the hanger structure 2. Each fitting 10 has an upper support bearing surface that is essentially planar and horizontal, to lean against the lower bearing surface of a crossbar 21 of the hanger structure 2.
As shown in FIG. 1c, each reservoir 1 is installed beneath the hanger structure 2 by engaging the edges of the metal fittings 10 in the facing lateral guides of a pair of adjacent crossbars 21. Said edges are placed onto the rails 22 of said lateral guides, and slide on said rails to penetrate into said engine pylon.
However, the engagement of the edges of the fittings 10 in the lateral guides to place the reservoir in the pylon is not easy, because of the dimensions of the openings made in the side walls of the pylon. The assembly is also not easy because such a reservoir 1 is generally rather voluminous (diameter of the order of 30 centimeters) and heavy (weight greater than 20 kilograms), and has to be carried at arm's length by one or more operators during its installation in the inside restricted space of the pylon.
It can be understood that new means are necessary to facilitate installation and removal of airplane fire extinguisher reservoirs.